Infrapatellar contracture syndrome, or patella infera, is a more advanced form of arthrofibrosis.
First published in 2006, and reviewed August 2023 by Dr Sheila Strover (Clinical Editor)
Some patients with this problem will essentially have normal flexion and extension of their knee but they will have increased contact pressures under the patella, or kneecap, and this will subsequently lead to pain and problems with functional activities – particularly things that involve weight-bearing, such as going up and down stairs, or hill climbing – things of that nature. When it becomes more severe, it actually creates a shortening, or contracture of the patellar tendon itself, and that becomes visible on X-rays – you can actually measure that shortening if you compare it from one side to the other, or if you compare it to what a normal relationship of the patellar tendon to the length of the patella would be - and that is known as patella infera or patella baja. That is a more advanced phase of this process.
So early on it just starts as scarring behind the kneecap and around the kneecap, which limits mobility of the kneecap and increases the joint contact pressures, and in the more advanced forms it actually creates shortening of the patellar tendon.
No spontaneous reversal
I personally have seen several cases of severe infrapatellar contracture syndrome and I have not seen it reverse once you start to develop the shortening of the patellar tendon. I have not personally seen it reverse unless there was a significant surgical intervention to lengthen the tendon or to reposition the tubercle -which are very advanced and invasive procedures which we would like to avoid if we can.
- Paulos LE, Rosenberg TD, Drawbert J, Manning J, Abbott P. Infrapatellar contracture syndrome. An unrecognized cause of knee stiffness with patella entrapment and patella infera. Am J Sports Med. 1987 Jul-Aug;15(4):331-41. doi: 10.1177/036354658701500407. PMID: 3661814.
- Ahmad CS, Kwak SD, Ateshian GA, Warden WH, Steadman JR, Mow VC. Effects of patellar tendon adhesion to the anterior tibia on knee mechanics. Am J Sports Med. 1998 Sep-Oct;26(5):715-24. doi: 10.1177/03635465980260051901. PMID: 9784821.